Any reason for this. They never tell us.
Have you compared last month's bill to this month's bill? You should be able to see what has changed. If you changed service with in the last year or so, "Special" pricing may change from the first 12 months, to a normal price for the rest of the contract. Taxes, fees, change when required.
You can wait for a Comcast employee to answer your post and communicate over more private messages.
Hello, wrsluke! Welcome to the Xfinity Forums!
MNtundraRET gave some great advice. You should be able to compare your last two bills in order to figure out what has changed. In these cases, it is often a promotion that expired. If you would like to send me a Private Message with your full name, I would be more than happy to take a look to see if that is the case and see if there are any promotions available to help lower your bill.
To send a private message, click my name "ComcastTambrey", then click "send a message".